From nsanchez@stanford.edu Sat Feb 18 15:24:38 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!nsanchez From: nsanchez@stanford.edu (Nadine Sánchez) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Feb18.152438.6160@stanford.edu> Date: Sat, 18 Feb 1995 15:24:38 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Nadine Sánchez Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab. ------------------------------------------------------------ From divanov@uu.net Sun Feb 19 08:50:38 1995 Path: ashpoly!cascade!brgate!saturno!uu!divanov From: divanov@uu.net (Dave Ivanov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Feb19.085038.9779@uu.net> Date: Sun, 19 Feb 1995 08:50:38 GMT References: <1995Feb18.152438.6160@stanford.edu> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Feb18.152438.6160@stanford.edu>, nsanchez@stanford.edu (Nadine Sánchez) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Dave Ivanov *PLONK* filter active for trolls. Sun SparcStation 20 - NetBSD 1.0 From lbrennan@u-tokyo.ac.jp Mon Feb 20 16:17:38 1995 Path: ashpoly!cascade!bigsur!u-tokyo!lbrennan From: lbrennan@u-tokyo.ac.jp (Lisa Brennan) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Feb20.161738.1936@u-tokyo.ac.jp> Date: Mon, 20 Feb 1995 16:17:38 GMT References: <1995Feb18.152438.6160@stanford.edu> <1995Feb19.085038.9779@uu.net> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Feb19.085038.9779@uu.net>, divanov@uu.net (Dave Ivanov) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- === Lisa Brennan === Dept of Electrical Engineering, University of Tokyo Department of Information Science "Measuring a record you own is listening, not piracy."